Stoker



Jan. 4,

Filed sein. 29, 1959 J. s. BENNETT.

STOKER 3 SheetSSheet 5 Patented Jan. 4, 1944 STOKER Joseph S. Bennett, Merion, Pa.,"assignor to American Engineering Company, Philadelphia, Pa., a corporation of Pennsylvania Original application May 13, 1937, Serial No.

142,389. Divided and this application VSeptember 29, 1939, Serial No. 297,068

3 Claims.

This application is a division of my co-pending application Ser. No. 142,389, led May 13, 1937, patented on April 2, 1940, under No. 2,195,808, and relates to furnace stokers, and more particularly to the overfeed section or extension grates of such devices.

One object of the present invention is to provide a generally improved extension grate construction which functions to both agitate and feed the partially consumed fuel and refuse toward the dump plates or ash pit of the furnace.

Another object is to provide an extension grate consisting of vertically and horizontally movable elements for agitating and feeding the partially consumed fuel and refuse toward the lash pocket or dump plates of the furnace.

Another object is to provide an exten-sion lgrate of the stated character adapted for use inconnection with fluid cooled stokers.

Other and more specific objects Will become apparent as the description of the invention progresses.

Of the drawings:

Fig. 1 is a longitudinal sectional view taken through one of the retorts of an underfeed stoker showing the invention applied to a stoker of the fluid cooled type.

Fig. 2 is an enlarged sectional view taken through the extension grate.

Fig. 3 is a plan view partly in section, of the construction shown in Fig. 2, with some of the parts removed to show the construction thereof.

Fig. 4 is a view taken substantially along line 4 4 of Fig. 3.

Fig. 5 is a longitudinal sectional view taken through an extension grate of a modified construction.

Fig. 6 is a plan view partly in section of the extension grate shown in Fig. 5, with parts broken away and others removed to show the construction thereof.

Fig. '7 is a plan view of the framework of an extension grate section of the type shown in Figs. 5 and 6, and

Fig. 8 is a side elevational view partly in section, taken substantially along line 8 8 of Fig. 7.

Fig. 9 is a side view of a bearing bracket.

Referring to the drawings, the numeral I designates generally a stoker consisting in the present instance of alternately disposed retorts 2 and tuyre rows 3. Fuel from a hopper 4 is fed to the retorts 2 by rams 5, driven by any suitable power mechanism indicated generally at B. The bottom of each retort 2 consists of a series of alternately disposed pushers 'l and dead plates 8, the pushers 1 being reciprocated by the power mechanism 6 through any suitable link and lever mechanism indicated generally at 9. The lower end of each retort is provided with an extended dead plate or coal plate I0. A series of overfeed or extension grate sections 9) provided at -the lower end of the Stoker feed the partially consumed fuel `and refuse to dump plates I2 which in turn may be actuated from time to time by any suitable operating mechanism to discharge the refuse accumulating thereon into an ash pocket I3. The extension grate `sections 9!! may also be actuated by the power mechanism 6 through any suitable link and lever mechanism indicated generally at Id. For a more detailed description of the operating means for the rams, pushers and extension grates reference maybe had to Uni-ted `States Patent No. 2,005,005.

Draft air is supplied to the furnace from a plenum chamber I5 which receives its air from any suitable fan or blower mechanism (not shown) through a communicating passage I6. Air is rsupplied tothe extension grate sections 99 from a common chamber Il' disposed therebeneath which communicates with chamber I5 by means of a communicating passage i8 having an adjustable damper I9 provided therein.

Mounted in cooling relation with each tuyre row 3, and a portion of the front wall 20 of the furnace, are fluid conducting tubes 9d. These tubes extend downwardly and form a portion of the overfeed section Si), and terminate at their lower ends ina transversely disposed header 22. The upper ends of tubes gli are connected to one of the steam drums of a boiler (not shown). Also mounted .in cooling relation with each coal or dead plate It are tubes 95. The rearwardly disposed ends of these tubes extend in parallel relation with the lower ends of tubes 94, and also terminate in header 22. The forwardly disposed ends of tubes 95 terminate kin a transverse header 24 vmounted in any suitable `manner beneath the Stoker I. Fluid from the boiler is supplied to header 2-2 by downtake connections 25, while uptake connections 2t connect lheader 24 with the boiler after a well known fashion.

The term front herein employed in the description vof the various lelements indicates the portion of the elements extending toward the front or power mechanism 6 of the Stoker, while the term rear indicates the portions extending toward the rear 'or dump plates I2.

Each extension grate unit consists of a series of rocking `or vertically movable elements 91, 'and a corresponding series of reciprocating elements 92, mounted on a stationary framework 93.

Secured by bolts 99, depending from tubes 94 and S5, are plates i923. These plates are provided with upper and lower slots ill and |02 respectively, for receiving elements Si and 92, and have a series .of apertures itil" through which draft air may pass. Each 'element 9i is also of angular construction, and comprises e. relatively narrow fuel engaging portion |03, and has de- 9| and 92, although the number of such elements' may be either increased or decreased without Y departing from the invention. Elements 9| are pivotally supported upon a rod |95 mounted inV a pair of rearwardly extending brackets |66, secured by bolts |93 or any other suitable fastening means to the front closing plate |68. The reciprocatory elements 92 are of substantially rectangular construction, each having a rounded nose or fuel engaging portion |99. The lower edge H3 of each element 92 rests upon the flat surface i i at the lower end of slot |62, as shown in Fig. 2. Elements 92 are also supported on bearing blocks l2 secured at the rearwardly disposed sides of tubes 911 and 95. The upper surfaces H3 of blocks H2 form a continuation of surfaces Iii, whereby extended bearing surfaces are provided for elements 92. The lower ends of bifurcated arms |94 of elements 9| are each provided with a pair of aligned slots i I4 through which extends an operating rod ||5. As shown in Figs. 3 and 4, operating rod |i5 also extends through apertures provided near the forwardly disposed ends of reciprocatory members 92. Rod ||5 has secured theretol a yoke ||6 to which is secured an operating rod li'i. Rod operates in any suitable bearing H8 provided in front closing plate E93, and may be operatively connected to any suitable power mechanism, such as that shown in Fig. 1. t therefore is seen that upon actuation of rod Eil and yoke ||6, the elements 9| of each section will be rocked about their pivots |95, and at the same time each of the elements 92 will be moved longitudinally. By this construction also, any masses of fuel or clinlrer supported on the overfeed section will be broken up by the action of elements 9|, and at the same time urged downwardly. The fuel and refuse will then be engaged by reciprocatory elements 92 and moved to any suitable refuse receiving device, such as to the dump plates |2 pivotally supported at the rear of the stoker..

Figs. 5 to S illustrate a further embodiment of the present invention. n this construction no fluid conducting tubes are employed with the underfeed or overfeed sections thereof. As shown more particularly in Figs. 5 and 6, this construction, like that shown in Figs. 2 to 4, comprises a series of rocking extension grate elements |25,

.and a corresponding series of reciprocatory elements E26 mounted on any suitable framework |2'i. Framework |21 comprises a pair of substantially triangular side plates |28 and |29, which are connected at the upper ends thereof by a cross member |39, and at their lower edges by a pair of spaced cross members |3| and |32. Secured to and extending upwardly from cross members i3! and |32 are a series of guide plates |33. The side plates E23 and |29 of each extension grate frame |27 have extending inwardly from the forwardly disposed edges thereof flanges |34, each having a pair of apertures provided therein. Flanges i3d are secured to the front closing plate E35 of the overfeed section in any suitable manner, such as by bolts |36. The inclined edges |33 of side plates |23 and |29 are provided with a downwardly and forwardly inclined bearing slot 33 for receiving the rounded ends |39, |39 of a square shaft |49 upon which the front ends of rocking elements |25 are supported, Also mounted at the ends of the square portion of shaft |40 is an operating member |4I. This member consists of a pair of arms |42 and |43 terminating at the forwardly disposed ends thereof in hub portions |44, each having a square aperture provided therein for receiving shaft |46.

The rearwardly disposed ends of arms |42 and |43 are integrally connected to a transverse, substantially angular plate or bail member |45 upon which the rearwardly disposed ends of elements 25 are supported. Each of the elements |25 has provided at the forwardly disposed end thereof a hub portion |46 having an open slot |41 provided therein which is adapted to engage the square portion of shaft |40, as shown in Fig. 5. The rearwardly disposed ends of elements |25 are secured to bail |45 in any suitable manner, such as by stud bolts |48. Extending rearwardly from elements |25 of each extension grate section are a pair of stationary plates |49. These plates are provided with a pair of downwardly extending apertured ears |56. Plates |49 rest upon the upper edges of vertical plates |33, and also upon the lower portion of the inclined edges |37 of side plates |28 and |29, as shown in Figs. 5 and 6, and the apertured ears |50 thereof are secured to certain of the vertical plates |33 in any suitable manner, su-ch as by bolts |5|, as shown in Fig. 5.

Elements |26 are of substantially rectangular construction, having upper and lower, substantially parallel edges |52 and |53, which terminate at the rearwardly disposed ends thereof in a rounded nose or fuel engaging portion |54. The forwardly disposed end of each element |26 is provided with an irregular-shaped slot |55, which is open at the forward end thereof, as shown in Fig. 5. The lower edge |53 of each element 26 is supported upon cross members |3| and |32, and is guided for operation between a pair of plates |33, or between a plate |33 and one of the side plates |28 or |29, as the case may be. Operating member |4| has depending from the hub portion of each of the arms |42 and |43 thereof a second arm |56. Arms |56 are each provided with a substantially vertical slot |51 near the lower end thereof for receiving certain elements of an operating mechanism |58, secured to a reciprocating rod |59 mounted in a bearing provided in the front closing plate |35. Operating member |58 consists of two spaced, rearwardly extending arms |66 and 15|, each of which having an aperture |62 therein disposed in registering relation with the vertical slots |57 of arms |56. A pair of pins |63 and |64- extending through these apertures |62 and slots |57 operatively connect member ilil with the operating mechanism |53. Thus, upon actuation of operating mechanism |58 a rocking movement will be imparted to member Sdi, and consequently to elements |25.

The rearwardly disposed ends of arms |60 and |6| are also provided with apertures through which extends an operating rod |65. The right hand end of this rod extends through an elongated slot |51 provided in side plate |29, as shown at |53. Rod |65 also extends through vthe slots |55 provided in elements |26 and actu- Vlowered until it assumes the position shown in Fig. 5. As therein shown, a downwardlyextending projection |69 is provided at the forward end of each element |26 which acts as an abutment to enable the operating rod |65 to actuate the elements forwardly after a feeding operation. In order to vary the extent of movement of each of the elements |26 an adjustable bolt is provided in projection |69. By adjusting this bolt the lost motion provided by the extended portion |1| of slot |55 may be varied.

Referring to Fig. 6, it will be observed that the end elements |25' of each of the extension grate units are somewhat wider than the intermediate elements |25 so as to extend over the top and beyond the outer extremities of side plates |28 or |29. These extended portions of adjacent elements |25', thereby occupy the space between adjacent units. It will also be observed that the stationary elements |49, |49 of each unit also extend beyond the side plates |28 and |29 of the framework and form an extension of element |25. In order to prevent dead spaces between the lower ends of adjacent grate units, an additional reciprocating element |26 is mounted for movement between side plates |2, |29 of the adjacent units. The rearwardly disposed ends of reciprocating elements |26 rest upon pairs of bearing extensions |12, |12 extending outwardly from the lower edges of side plates |28 and |29. The forward end of each element |26' is also provided with an irregularlyshaped slot |55' similar to the slot |55 provided in elements |26. This slot receives the extended portion |68 of a corresponding operating rod |65. Also extending between the side plates of adjacent extenson grate units is a bearing bracket |13 having an open bearing slot |14 provided at the rearwardly disposed end thereof which receives the rounded end portions of shafts |40. These brackets |13 thus afford additional bearings for these shafts.

From the foregoing description it is apparent that the various elements of the extension grate units may be readily installed upon the framework, or in case damage should occur thereto during operation of the stoker, they may be readily renewed. To renew one of the elements |25 or |25 it is only necessary to remove bolt |48, and then lift the element from engagement with the square portion of shaft |40. A new element may then be readily inserted in position and secured to the bail |45. To renew an element |26 it is only necessary t0 tilt the same until shaft |65 lies in the lower portion |18 of slot |55, and to then move element |26 rearwardly to clear the shaft. To replace such an element with a new one the process is reversed. The element is actuated so that the lower portion |18 of slot |55 engages shaft |65 and clears the downwardly extending projection |65. The element is then lowered until it occupies the position shown in Fig. 5. To renew one of the elements |49 it is only necessary to remove bolts |5| when the same maybe lifted from the framework. Also by removing operating pins |63 and |64 the member |4I, and all of the elements |25 and |25' supported thereon, may be lifted out of the bearings provided in side plates |28 and |29, and brackets |13.

In operation draft air may pass to the fuel bed between elements |25 and |25', and also between the elements |26 and |26', as well as between stationary elements |49. However, in order to allow a greater quantity of air to now into the fuel bed, apertures and |16 may be provided in the elements |25, |25 and elements |49 respectively.

From the foregoing description it is seen that the various embodiments of the invention herein shown are extremely effective in agitating the fuel, thereby breaking up clinker and masses of fuel and feeding the same to dump plates provided at the rear of the stoker. By this construction eflicient combustion of the fuel is effected, as well as the elimination of large clinker masses, which often occur during operation of the furnace.

While the various embodiments herein shown and described are admirably adapted to fulll the objects primarily stated, it is to be understood that the invention is not to be limited thereto since it may be embodied in other forms, all coming within the scope of the claims which follow.

What is claimed is:

1. An extension grate for stoker furnaces, comprising a stationary framework, a transverse member supported in said framework, an upper series of rocking grate elements detachably supported on said member, an operating member for said rocking elements, means for detachably securing said elements to said operating member, actuating means for said member, a lower series of reciprocatory grate elements mounted in said framework, means for detachably securing said last mentioned elements to said actuating means, and adjustable means between said reciprocatory elements and said actuating means whereby the extent of movement of said reciprocatory elements may be varied.

2. An overfeed section for stoker furnaces, consisting of a plurality of extension units arranged in side by side relation, each of said units comprising a framework, a series of rocking grate elements supported in said framework, a corresponding series of reciprocating elements also mounted in said framework, stationary grate elements disposed between said rocking and reciprocating elements, certain of said rocking and sta tionary grate elements extending beyond the outer extremities of the associated framework, an operating member for actuating said rocking and reciprocatory elements, a rod connecting said reciprocatory elements to said operating member, one end of said rod extending laterally from said framework, and an additional reciprocatory element disposed between the frameworks of adjacent units and operatively connected to the extended portion of said rod whereby said last mentioned reciprocatory element moves in unison with the reciprocatory elements of the associated extension grate unit.

3. An extension grate for stoker furnaces comprising a stationary framework, a transverse member supported in said framework, an upper series of substantially L-shaped rocking grate elements supported on said member, one portion of each of said grate elements constituting the fuel supporting portion thereof, while the other portion thereof constituting an operating element, an operating member operatively attached to said last mentioned portion of said elements, a lower series of reciprocatory grate elements mounted in said framework, means for attaching said reciprocatory elements to said operating member, and Stationary grate elements disposed between said rocking and reciprocatory grate elements.

JOSEPH S. BENNETT. 

